(a) Field of the Invention
The present invention is related to a paper guide, and more particularly, to a mobile paper guide adapted to an automatic document feeder (ADF) to sort front edge of paper sheet.
(b) Description of the Prior Art
Automatic paper sent is one of the basic functions for many types of office machines. Therefore many office machines including facsimile machine, photocopier or scanner is provided with a mechanism of ADF to feed the paper sheets stored in paper tray into the machine. In the course of the transfer between two given locations, e.g., the paper tray and where inside the machine for the paper sheet fed pending for next process, a paper guide adapted to the ADF is usually used to retain and align the paper sheet. Referring to FIG. 1 of the accompanying drawing for a Mechanical Paper Guide disclosed in a U.S. patent, U.S. Pat. No. 6,557,848 B2, the mechanical paper guide to control the entrance of paper sheet into an ADF includes a platen 35a, a motor (not illustrated) for driving the platen 35a to rotate, a cam 32a, a paper guide arm 31a, and an elastic clip 33a. The cam 32a includes a first protruding block 321a and a second protruding block 322a. The cam 32a as driven by the platen 35a causes both of the first and the second protruding blocks 321a, 322a to rotate. A pin 3121a as the point subject to the force is provided on the paper guide arm 31a. The pin 3121a in responding to the push by the rotation of the first protruding block 321a causes the paper guide 31a to ascend. As the paper guide arm 31a is moving up, it is engaged by the elastic clip 33a thus to stay at paper feeding position. The elastic clip 33a in responding to the push by the rotation of the second protruding block 322a creates displacement to release the paper guide arm 31a for the latter to descend into a retaining position. However, as taught, the mechanical paper guide of the first prior art is comprised of too many components. The production cost is comparatively higher since all the components have to be made one by one with further consideration of the allowance between any two components and the individual location of all components must be in their exact location before confirming the state of assembly due to that all the locations of those components for assembly are different from one another. Therefore, the first prior art prevents the assembly in one step. Furthermore, with the increased variables during the assembly, any component falling out of place would fail the entire structure to attract more problems and increase service cost.
Now referring to FIGS. 2A and 2B for a Paper Feeding Installation & Method of a second prior art published under #TW568833 in Taiwan Gazette, a paper guide 15b as disclosed includes a cam 15b-1 and a guide plate 15b-2 on each of both sides of the paper guide 15b. The cam 15b-1 is provided on a platen 150b to turn around an axle center IV to stride over a housing W1. A torque limiting device 152b provided on another end of the platen 150b includes a first plate 152P1, a second plate 152P2, and an elastic member 152S. Wherein, the elastic member 152S contacts the platen 150b and a gear 150G as respectively compressed by the first plate 152P1 and the second plate 152P2. The guide plate 15b-2 relates to a plate in a shape approximating the letter L. One protruding end of the cam 15b-1 is compressed to contact the guide plate 15b-2 while multiple sheets of paper P are aligned and held in position by taking advantage of the side of the guide plate 15b-2. The guide plate 15b-2 is locally accommodated in two chutes 108b of a base housing H-2. The lower end of the guide plate 15b-2 is retained by both locking holes 108H respectively disposed in those two chutes 108b. The guide plate 15b-2 by sticking its lower end into both locking holes 108H achieves the purpose of aligning and positioning those multiple sheets of paper P. As taught by the second prior art, each of both sides of the paper guide 15b must be provided with the cam 15b-1 and the guide plate 15b-2. In the prior art, both guide plates 15b-2 are made integrated in one piece that provides the paper guide function from top in a striding fashion. However, in practice, the integrated guide plate 15b-2 is vulnerable to be deformed and warped to lean to either side that prevents both sides leveled, thus fail to provide sorting the paper sheet at the same time by both guide plates 15b-2. Furthermore, as multiple gears 10 are provided between two guide plates 15b-2, both guide plates 15b-2 are in fact not arranged in symmetric. As a result either guide plate 15b-2 provided with a longer swing arm could get easily fall out of position due to leverage effects to consume more service cost.